Power take-off device, particularly for timepieces



Aug. 7, 1956 e. G. ENSIGN ET AL 2,757,545

POWER TAKE-OFF DEVICE, PARTICULARLY FOR TIMEPIECES Filed Aug. 4, 1953 4Sheets-Sheet 2 30 as 5W 1 113a r! I g a; 11ml; i* V A I mm INVENTORSGeorge G. Ens zgn,

ATTORNEYS Aug. 7, 1956 5. G. ENSIGN ET AL 2,757,545

POWER TAKE-OFF DEVICE, PARTICULARLY FOR TIMEPIECE S F iled Aug. 4, less4 Sheets-Sheet s INVENTORS George G. Z5 '?z$z:57n, Glenn TSOPG? andOSsz'an Lunda/LZ h 622., @144 v hmz,

ATTORNEYS Aug. 7, 1956 5. G. ENSIGN ET AL 2,757,545

POWER TAKE-OFF DEVICE, PARTICULARLY FOR TIMEPIECES Filed Aug. 4, 1953 4Sheets-Sheet 4 INVENTORS George 6?. E115 {971,

Glenn ZSgoev: and OS-SZ an Luna'afi Z v hm ATTORNIEYS United StatesPatent POWER TAKE-OFF DEVICE, PARTICULARLY FOR TINIEPIECES George G.Ensign and Glenn T. Soper, Elgin, 111., and

Ossian Lundahl, Orlando, Fla., assignors to Elgin Naiional WatchCompany, Elgin, 111., a corporation of linois Application August 4,1953, Serial No. 372,292

17 Claims. (Cl. 74-88) This invention relates to energy-transfer orpower take- -'off structures for transmitting intermittently the effectsof an oscillating movement to an element having a unidirectional orintegrating motion, and is particularly of value in watches and the likewhere small amounts of energy are taken from an oscillating balance andcaused to move the train.

A feature of the invention is the provision of an oscillating element, atransfer means having projections engaged and directly moved during apart of each stroke of an oscillation of said element, and a detent andstop system which cooperate by limited movement to permit advancement ofthe transfer wheel during a forward stroke and which detent cooperateswith the transfer means during the return stroke by a tangentialyielding to permit return of the transfer means for passing of theoscillating element and thereafter serves by resilient tangential returnto restore the transfer means to position for a new advancing engagementduring the following stroke.

Another feature is the provision of an oscillating element, a transferwheel having teeth directly engaged and directly moved during a part ofeach stroke of an oscillation of said element, and a detent membereffective upon the transfer wheel to procure tooth-by-tooth forwardmovements thereof and also effective by tangential motions to permitresiliently-opposed return movements thereof and thereafter to restorethe transfer wheel to an engagement-receiving position.

A further feature is the provision of a watch mechanism including abalance and hairspring assembly, a train, a transfer wheel connected formoving the train, an element oscillated with the said assembly andengaging the transfer wheel during the forward and return strokes, and aresilient element moved by the transfer wheel to permit step-by-stepadvancement of the transfer wheel during the forward strokes of theoscillation cycles and effective by tangential motions to permitretrograde movement of the transfer wheel with subsequent inducedrestoration thereof during the return strokes of the cycles.

A further feature is the provision of a mechanism including anoscillating element, a transfer wheel directly engaged and moved backand forth by the element, and a member acting upon the transfer wheel topermit a limited and resiliently opposed return movement with automaticrestoration thereafter and to permit step-bystep advancements thereofwith limitation upon the maximum advancing per cycle.

A further feature is the provision of a mechanism including anoscillating element, a toothed transfer member directly engaged andmoved back and forth by said element, and a resilient movement limitingmember cooperative with the transfer member to permit the same to moveone of its teeth past the said limiting member dur ing forward strokeand to permit retrograde movement of the transfer member during returnstroke by a tangential resilient yielding while preventing the return ofthe tooth past the said limiting member and effective after theoscillating element has escaped from the transfer member during suchreturn stroke to restore the transfer member to a position ready toreceive the oscillating member in the next forward stroke thereof, saidlimiting member being effective to prevent the transfer member fromoccupying a position while free of the oscillating element in which thetransfer member is not ready for cooperation with the said oscillatingelement.

A further feature is the provision of a mechanism including anoscillating element, a transfer wheel acted upon by the said element tobe moved back and forth thereby, and a member acting upon the transferwheel and having a resiliently opposed tangential movement during thereturn movement of the transfer wheel and a pawl action during theforward movement of the trans fer wheel, said transfer wheel beingpermitted to move through arcs determined by tooth engagements with saidmember wherewith the said member is effective to prevent the transferwheel from remaining at rest in any position wherein it is not ready forengagement by said element.

With these and other features as objects in view, illustrative forms ofpractice are shown on the accompanying drawings, in which:

Fig. l is a plan view of a watch assembly including an electricallyactuated balance, a train, and a power transfer therebetween inaccordance with this invention;

Fig. 2 is an upright section, at a larger scale and substantially onbroken lines 2-2 of Figs. 1 and 3, showing transfer parts;

Fig. 3 is a plan view of the cooperative parts, substantially on brokenline 33 of Fig. 2, with other parts partly broken away and partlyomitted for clearness;

Fig. 4 is an upright section substantially on line 44 of Fig. 3;

Fig. 5 is a diagram corresponding to a part of Fig. 3 but with the partsin another moved position; a

Fig. 6 is a similar diagram, with the parts in a thir position;

Fig. 7 is a plan view as in Fig. 3, of another form of construction;

Figs. 8 and 9 are diagrams of certain parts as in Fig. 7, showingpositional limits of movements.

As shown in Figs. 1 to 6, a watch assembly has a pillar plate PP withassociated bridges and balance cock BC for supporting the various staffsand parts of a train and the balance staff BS having a balance wheel rimBW, a collet HSC connected to a hairspring HS which at its other end isengaged with the hairspring stud HSD, a collet RC having thereon acontact fin 50 and a so-called jewel or roller pin 51. The dial D isconventionally shown. The contact fin 50 engages and moves a contactblade CB near the neutral axis of an oscillation stroke, therebyproducing contact of blade CB with a side contact 60 during each cycle:the blade CB and contact 60 are connected by the conventionally shownconductors with a coil C and a battery B so that an electrical impulseflows during each cycle to energize the coil C and thereby produce amagnetically induced action upon the balance wheel BW for maintainingthe same in oscillation.

During the forward stroke of the balance system, the pin 51 encountersthe star wheel SW, shown with eleven teeth or points, but it will beunderstood that any suitable number may be employed. The star wheelpinion 87 has a like number of points, so that for each movement of thestar wheel by the roller pin 51, the wheel 106 meshing with the starwheel pinion 87 is advanced by'one tooth.

A spring 92 has a bent end 92a for engagement with the successive starwheel points and is supported by a rotatable stud 90 mounted with tightfriction in the pillar plate PP. A rotatable block 91 is mounted by itseccentric pivot 91a likewise with tight friction in the pillar plate PP,and serves to limit the movement of the spring end 92a upward in Figs.3, and '6. The block 91has a kerf 91k for a screwdriver and, by rotatingit, the position of engagement of the spring end with the star wheelpoints may bevaried and therewith the positioning of the star wheelpoints along the path of the roller pin 51 while the points are at rest(e. g. as in Fig. 3) with a :point SW-r ready to receive the roller pin51 for advancement thereby. Rotation-of the-stud 90 by engagement of itskerf 90k permits establishing a desired preliminary tension in thespring arm92 as it rests against the block 91.

In operation, as the balance .wheel oscillates, its staff 'BS carries*the roller collet RC through like angles. Assuming 'that the balance isin its clockwise stroke, as in dicated by thearrow in Fig. 3, the rollerpin 51!. encounters the star wheel point SWr near the neutral axis,substantially-at the time that the fin moves the contact blade CB intoengagement with the fixed contact 6t) and closes the circuit energizingthe motor coil C. The star Wheel SW is thereupon moved in acounterclockwise direction from the position of Fig. 3 toward that ofFig. 5, at which the non-concentric arcuate paths of the roller pin 51and of the star wheel points cause the roller pin to escape from thestar wheel point SW-r: immediately prior to this escape, another starwheel point SW-p has engaged and pressed the spring end 9211 outward tothe dotted line position of Fig. 5, and after passing the spring end haspermitted the spring end to return to the full line position. It will benoted that the star wheel SW can move beyond the position shown, bymomentum, but its forward movement is restricted by the possibleencounter of a nextsucceeding point SW-q against the spring end 92a, as

indicated by'dash lines in Fig. 5, wherewith the star wheel point SW-sthen overlying the roller collect RC may occupy any position in the restzone between the full line and dash line positions shown but isprevented from entering the free zone between the dotted line positionSW-s and the full position shown for the point SWr which has just beenadvanced.

After escaping the point SWr, the roller pin 51 is carried to the end ofthe clockwise stroke of the balance system, and then returns in itscounterclockwise stroke. The roller pin 51 passes the point SWr, andencounters the point SW-s and acts upon it'to cause a retrograde orclockwise movement of the star wheel SW until escaping therefrom asshown by the full line position in Fig. 6. The retrograde movementof-the star wheel-SW causes the tooth SW-p which has just passed thespring end 92a to be moved against this spring end and to cause thespring portion 92 to flex from the dotted line to the full line positionof Fig. 6. When the roller pin 51 escapes from the point SWs, the energystored in the flexed spring 92 now causes the spring to return, intothedotted line position of Fig. 6, until the spring is stopped by theblock 90, therewith pushing the point SW-p and the star wheel ahead ofit, possibly projecting it farther but again with limitation to the restzone of Fig. 5 upon engagement of the succeeding point SW-q with thespring end 92a as shown by dash lines in Fig. 6.

Thus the star wheel SW is caused to make a forward movement by theroller pin 51, followed by a retrograde passing movement by-therollerrpin 51, and'finally a forward movement byspring action, for eachcycle of balance action and therewith producing a net forward motion ofwheel 106 by onetooth.

In practice, the train load upon .the wheel 1% acts to limit the freeforward movement'of the :star wheel after i'theuroller pin 51 escapes"the star wheel point, while a greater free forward movement occurs asthe spring "92 acts'until'sto'ppe'd by'theblock 91. Hence, thestroboscopic effect-is that of the points occuping two successivepositions. The back-lash 'or'play in-thetrain has been found suflicientin practice to prevent any apparent retrograde movement of the secondhand during retrograde movement of the star wheel, so that a 300 beatsystem has the appearance of a 300 beat continuously forward movement ofthe second hand, in lieu of the beat effect presented when the totalforward train movement is produced by the roller pin 51 during a single,e. g. clockwise stroke.

In the modified form shown in Figs. 7, 8 and 9, the roller collet RCcarries the contact fin 5'0 as before, and a pin 5i. formed as acylinder of semi-'circularsection, the diametrical plane facethereofbeing radial to the axis of the star wheel SW-a when the pin 51engages a star point (full line, Fig. '9) at the rearward limit ofpermissible rest position forthe star wheel.

The star wheel SN-a is illustrated as having eleven equal-spaced teetheach having an edge 46 for engagement by the-pin 51 during theadvancement and an edge 41 for such engagement during the return strokeand passing action. These teeth are illustrated as thin, with the edges40 straightandradial, and the edges 41 straight and nearly radial: thusthe bottoms 42 at the tooth gaps are longer than with the form in Figs.1-6.

The detent spring in Fig. 7 has an end portion 192 mounted in a chordalgroove of the frictionally tight adjustment stud 190 having the kerf191. From the portion 192 extends a portion 192a which is essentially atright angles when theparts are free of stress, and from the portion 192aextends a-portion 19212 which is free of the star wheel points. At theend of portion 192b, the detent-spring has a bight 192s curving throughabout degrees and joining the portion 192d which lies in the plane ofthe star wheel for engagement by :the points thereof At the free end,the detent spring has an angularly directed portion 192@ alsocooperative with the points.

An adjustment block 194 projects from the frictionally fitting stud 194ahaving a kerf 194E). This block 194 provides an adjustable stop for thedetent spring and limits the movement-thereof during the advancing ofthe star wheel SWa, but leaves the detent spring essentially free tomove during return movements of the starwheel.

In operation of the device of Fig. 7, as the balance oscillates, duringthe forwarder clockwise stroke as shown by thearrowtFig. 8), the pin 51encounters a star wheel point and causes the star wheel to turncounterclockwise, and .escapestherefrom when the pin and star wheel arefor example in the position shown in dotted lines in Fig. 9. Thestarwheel acts at another of its points .by pressing outward upon theportion 192d, therewith flexing (Fig.8) the detent spring at the bight192C and in the portions 192d, 192b, with insignificant change in theportion 192a, it being noted that the block 194 stops anybodily-movement of the portion 192a. Near the end of the engagement ofpin 51 with the star wheel point which is being .driven, .the pointacting on the detent springpasses the junction of portions 192d, 1922,i. c. it goes ,past the position shown in Fig. 8, .and the :portionl92eof .the detent spring. acts to accelerate the star. wheel, which drawsaway from the pin 51, so that the power transfer from the pin 51 to thestar wheel is eonfinedto the time while a star wheel point is pressingthe detentspring outward, i. e. for a limited are closely at the neutralaxis of balance oscillation.

When the portion 192:: accelerates the star wheel, it may impart amomentum effect which causes the star wheel to pass beyond the dottedline position of Fig. 9; and inparticular the star wheel may have itspoints occupy any position within a large range, e. g. the point .SW-qmay lie in any position in the range indicated by the radial lines AandB in Fig. 7.

'The forward motion of the star wheel is repeated by "the pinion 87, andthus delivered. to the train.

During the return or counterclockwise stroke of balance oscillation,Fig. 9, the pin 51 passes the star point which has just been driven,noting the range of positions possible to the star wheel as shown inFig. 7. The pin 51 strikes the edge 41 of the next succeeding point, andcauses the star wheel to turn backward or clockwise: when the star wheelattains a position as shown by full lines in Fig. 9, the pin 51 escapesand the balance then completes its return stroke. The retrogrademovement of the star wheel causes a point to engage the portions 192e ofthe detent, with a composite effect (Fig. 9) by which the portion 192afiexes and leaves the block 194, and also there is a minor outwardmovement of portions 192d and 192e, the portion 192d is presentedinitially to the point during the forward stroke at an angle of about 30relative to the tangent line, whereas during the return stroke, theportion 1922 is presented initially at an angle of 45, and hence thereis a greater component of forces in the directions radial to the starwheel axis during the retrograde movement, and the detent spring alsoacts through a longer length, so that the spring tends to have its freeend portions move bodily rather than to flex.

When the pin 51 escapes the star wheel point during the return stroke,the detent spring acts resiliently to cause the portion 192e to move thestar wheel clockwise again until it comes to rest in a position withinthe range A-B shown in Fig. 7, with a net forward movement by one toothduring the cycle.

In practice, as before, the train can have a backlash from the hands,amounting a permissive movement of 9 at the pinion 87, relative to thefirst wheel 106 of the train: and this corresponds to the 9 ofretrograde star wheel movement during the passing action of the pin 51during its return.

It will be noted that the form of Figs. 7 to 9 has the positions of thedetent spring presented at different angles to the tangent, relative tothe transfer wheel SW, the angle of the retrograde-limiting portion192:; being steeper relative to a radius from the transfer wheel axisthan the angle of the portion 192d. Hence the effort required forpressing the portion 192d outward for the forward stepping movement islow, while the spring responds to retrograde movement with itsrelatively tangential yielding during normal retrograde arcuate movementof the wheel SW as produced by the pin 51. In this form, however, thesystem is protective in event of excessive movement of the wheel SW fromany cause: for example, if the train is turned by a resetting device, tomove the wheel SW counterclockwise, the detent yields as usual for eachpoint, while for clockwise movement of the wheel SW, the detent yieldsas during retrograde movement induced from the jewel pin and can gobeyond this position and permit the points to pass in succession, ineach case without damage to the detent.

It will be understood that the invention is not limited to theillustrative forms of practice, but may be employed in other ways withinthe scope of the appended claims.

We claim:

1. A power take-01f structure for an oscillating device and efiectingintermittent net forward motion of a driven element, comprising transfermeans in driving relation to said driven element and having projections,a part oscillated by said device and efiective to engage and moveprojections of said transfer means during the forward and backwardstrokes and thereby move said transfer means back and forth, and aresilient detent member cooperative with projections of said transfermeans and supported for radial movement relative to the transfer meansupon forward motion of the transfer means whereby to permitelement-advancing passage of a projection and for limited resilientlyopposed tangential movement relative to the transfer means upon backwardmotion of said transfer means whereby to prevent retrograde passage of aprojection.

2. A power take-off structure for an oscillating device and effectingintermittent net forward motion of a driven element, comprising transfermeans in driving relation to said driven element and having projections,a part oscil-. lated by said device and effective to engage and moveprojections on said transfer means during the forward and backwardstrokes and thereby move said transfer means back and forth, a resilientdetent member cooperative with porjections on said transfer means andsupported for movement in one direction upon forward motion of thetransfer means whereby to permit element-advancing passage of aprojection and for limited resiliently opposed movement in anotherdirection upon backward motion of said transfer means whereby to preventretrograde passage of a projection. v

3. A power take-ofi structure for an oscillating device and effectingintermittent net forward motion of a driven element, comprising a partoscillated by said device, transfer means engaged and moved forward andbackward by said part during the forward and return strokes thereof andin driving relation to said driven element, a resilient detent membersupported for radial and tangential movement of a portion thereofrelative to the transfer means successively by the transfer meanswhereby radial movement is imparted thereto by the transfer means duringforward movement thereof and tangential movement is imparted thereto bythe transfer means during return movement thereof, said tangentialmovement being effective for resiliently opposing such return movement,and a stop limiting tangential movement of said member during theforward stroke of said device.

4. A power take-off structure for an oscillating device and effectingintermittent net forward motion of a driven element, comprising a partoscillating with said device, a transfer wheel having teeth engaged andmoved by said part during the forward and return strokes, resilientdetent member having two connected angularly-directed legs, the end ofone of said legs being supported and the end of the other of said legsbeing located for engagement by the teeth of the transfer wheel wherebythe latter said end can move radially and tangentially relative to thewheel, and a stop for restricting the tangential movement in onedirection.

5. A power take-off structure for an oscillating device and effectingnet forward motion of a driven element, comprising a transfer means indriving relation to said driven element, a part oscillated by saiddevice and effective to move said transfer means back and forth in timewith its own oscillation, and a detent member effective upon thetransfer means for permitting successive advancing movement of thetransfer means in one direction and effective thereon for limitingreturn movement thereof in the other direction and effective to impose arestoring movement in said one direction following a said returnmovement.

6. A power take-off structure for an oscillating device and efiective toprocure intermittent net forward motion of a driven element, comprisingtransfer means oscillated by said device and in driving relation to saidelement, and a detent member cooperative with the transfer means andyielding relative to the transfer means in one direction of movement ofsaid means for permitting element-advancing motion thereof during aforward stroke and yielding in another direction with the transfer meansduring a retrograde stroke thereof and thereafter returning with saidtransfer means in the said elementadvancing direction of movement.

7. A power take-off structure for an oscillating device and effective toprocure intermittent net forward motion of a driven element, comprisingtransfer means oscillated by said device and in driving relation to saidelement, and a detent member cooperative with the transfer means andyielding radially relative to the transfer means for permittingelement-advancing motion thereof during a forward stroke and yieldingtangentially relative to the transfer means during a retrograde stroke"'7 thereof and R thereafter returning tangentially in the saidelement-advancing "direction of movement.

'8. A power take-01f structure for a mechanism having anoscillating'devi'ce and effective to procure-intermittent not forwardmotion of a driven element, comprising transfer means oscillated bysaid'device and in'driving relation to said element,and a detent membercooperative with the transfer means and yielding relative "to thetransfer means "in one direction of movement of said means forpermitting element-advancing motion thereof 'during'a forward stroke'andyielding in another direction with the transfer means 'during aretrograde stroke thereof and thereafter returning from saidotherdirection'inthe said'element advancing direction of movement, 'sai'ddetent 'memberpresenting surfaces for initial 'engag'ementby saidtransfer means, said surfaces being angularly disposed relative to'oneanother'and a different respective anglesrelative to a line radialto'the axis of thetransfer means whereby up'on excessretrograde movementof said transfer'means the latter can repass said detent "member in thereverse direction.

being 'angularly disposed relative to one another and at ditferentrespective angles relative to a'line radial to the axis of the transfermeans whereby upon excess retrograde movement of said transfer means thelatter can repass said detent member in the reverse direction.

10. Apower'take-off structure for an oscillatory element and effectivefor moving a 'rotary'element, comprising a part oscillated by'saidoscillatory element, a

toothed transfer wheel engaged and moved back and 'forth by said partand connected for driving said rotary element, a'detent'member supportedforradial and tangential movement of a portion thereof relative to thetransfer wheel successively by the wheel teeth, and a stop limitingtangential movementof said'detent member during one stroke of said part.

11. A structure as'in claim 10, in which the member is a blade springhaving two angularly'directed leg portions, onev portion having its endsupported and'the other portion being presented'for engagement by thetransfer wheel teeth, and said stop engages the bla'cle'spring at thebight between saidportions.

l2. A structure as in claim 10, in which the member is a bladespring'having successive angularly directed "leg portions, one portionhaving its end supported, and

two other adjacentportions presenting their bight for engagement by thetransfer wheel teeth, the one of said other portions which is engaged bya wheel tooth during retrograde movement'having a greater angle to thewheel radius'which extends to said bight than the other of said otherportions.

13. A power take-off structure'for an oscillating device for net forwardadvancement of a'driven element,

comprising a part moved forth'and back during the strokes of the device,a transfer member included in saiddriven element, said partbeingetfective'to move the said transfer member in a forward directionduring its own forward stroke and to move the same in a rearwarddirection during its own rearward stroke, adetent member engageable bythe transfer member and resiliently supported'for movements indifferentdirections at angles to one another wherewith during the forward strokessaid transfer member causes resilient yieldings and returns of thedetent-member in-one of saiddirect-ions so that parts of the transfermember 'successivelypass the detent member and produce forwardadvancements of said driven element, and during the rearward strokessaid transfer member causes resilient yieldings and returns of thedetent member in another said direction in controlling relation to thetransfer member and without retrograde movement of the transfer memberpast the detent member, and a stop forlimiting the return'of the detentmember following a movement in saidother direction.

14. A power take-off structure for an oscillating device and eifectingart-intermittent forward and'backward movement'with a net forwardadvancement of a-driven element, coinprisinga part oscillating with saiddevice, a transfer toothed member included in thedriven element, theteeth of which member are in the path of said part and moved in onedirection during the forward stroke of said-device and moved'inthe'opposite direction during the rearward stroke thereof, a-resi1ientdetent member supported for movement of a portion thereof successivelyby-the teeth in two different directions at an angle'one with respect totheother, wherewith during the forward strokes the movements of theteeth of said toothed member cause 'yieldings of said portion in onedirection and theteeth'successively pass the same withforward'advancement of said driven element, and during the rearwardstrokes the movements of said teeth'of said toothed'member causeyieldings'of said portion in another direction withoutretrogradepassings of the teeth, and a stop for limiting the 'last'mentionedmovement of said resilient detent portion during the forward strokes ofsaiddevice.

stroke thereof, a resilient detentimember supported for radial andtangential movement of a portion thereof relative to the transfer wheelsuccessivelybythe'wheelteeth,

wherewith during the forward strokes the movements 'of'the teeth of saidwheel cause radial yieldings of said portion and the teethsuccessivelypass the same with forward advancement of said driven element, and dur-'ing the rearward-strokes the'rnovements of the teeth'of said wheelcause tangential yieldings of said portion without retrograde passingsby the teeth, "and astop for limiting tangential movement'of saidportion during the forward strokes of said device.

16. A power take-off structure foran 'oscillating'device and effectingintermittent net forward motion of a driven element, comprising a partoscillatingwith the said device, a transfer wheel having teeth andpositioned for cooperation with said part whereby to be moved back andforth by said part during thef'orward and return strokes of said device,a resilient'detent member supported for radial and tangential movementrelative to the transfer wheel of a portion contacted and movedsuccessively by the wheel teeth and positioned relative to'the path ofsaid teeth so that saidwheelhas'limited freedom of position while atrest but is limited in its free movements by said detent member wherebyin any rest position of the wheel there are two teeth thereof presentedin the path of movement of saidpart, said part being effective duringthelforward stroke to vcause a tooth of the transfer wheel to produce aradial movement of a contacted part of said detent member whereby thetransfer wheel advances forwardly "pastthe'detent member, anda stop forlimiting tangential'movement of said detent member during such'forwardstrokeof said part, said part being effective during its return strokefor causing backward movement of the transfer wheel with engagement of atooth thereof against the said detent member for effecting a relativetangential movement of the detent member Without retrograde passage ofsaid latter tooth past the detent member, said detent member beingeffective upon release of the transfer wheel by said part during thereturn stroke for effecting a limited return of the transfer wheel inthe forward direction.

17. A power take-off structure for an oscillating device and effectingintermittent net forward motion of a driven element, comprising atransfer wheel having teeth and connected to the driven element, meansfor actuating said transfer wheel and including a part oscillating withsaid device and effective during the forward and return strokes of saiddevice to move the transfer wheel back and forth, a resilient detentmember supported for movement in two directions at angles to one anotherof a portion thereof contacted and moved successively by the wheel teethand positioned relative to the path of said teeth so that the wheel haslimited freedom of position while it is not being moved from saidactuating means but is limited in its movements within said freedom ofposition so that at least one tooth thereof is always presented for suchactuation in either 10 direction, said part being effective during onestroke of said device to cause a tooth of the transfer wheel to producea movement of a contacted part of said detent member in one saiddirection whereby the transfer wheel advances forwardly past the detentmember, and a stop for limiting motion of said detent member in theother said direction during such one stroke of the device, said partbeing effective during the succeeding stroke of the device for causing atooth of the transfer Wheel to produce a movement of a contacted part ofsaid detent member in the other said direction without retrogradepassage of said latter tooth past the detent member, said detent memberbeing effective upon release of the transfer wheel from said part duringthe return stroke for effecting a limited return of the transfer Wheelin the forward direction.

References Cited in the file of this patent UNITED STATES PATENTS1,974,054 Popp Sept. 18, 1934 2,084,226 Strahm June 15, 1937 2,266,015Fink Dec. 16, 1941 2,305,666 Bolsey Dec. 22, 1942 2,572,989 Contant eta1. Oct. 30, 1951

